Idenix Pharmaceuticals Inc. (IDIX) is shelving the development of two hepatitis C therapies that had been stopped by U.S. regulators after a competing therapy was linked to heart risks. The Food and Drug Administration put a hold on studies of the company’s nucleotide polymerase inhibitors IDX184 and IDX19368, after safety issues arose while Bristol-Myers Squibb Co. (BMY) tested a hepatitis C therapy in the same family of compounds, called guanosines. Idenix is among companies including Bristol-Myers and Gilead Sciences Inc. (GILD), seeking new therapies for the viral disease that affects as many as 170 million people worldwide. The experimental drugs are designed to be taken as pills with shorter treatment durations and fewer side effects than the current medicines. While Idenix, based in Cambridge, Massachusetts, has found no evidence of severe heart problems with patients on its IDX184, the FDA said the clinical holds would remain in place, the company said today in a statement. Idenix hadn’t begun testing IDX19368 in people when the holds were issued. Idenix said it would stop development of the two drugs and proceed with different versions of nucleotides, called uridines. Proof-of-concept testing of the therapies is planned before July, the company said in its statement.